vignette on bottom only

I hope someone may be able to help. I am using a 30D and up to 3 strobes for a small basement studio. I am just starting to practice with studio lighting.

I tried a few shots last night and repeatdley got a vignette on one side of all my photos. It always shows up on the side where the bottom of the camera was. For example if I held the camera in a normal view it was at the bottom of the image. If I held the camera vertical it was on the right side. I also tried holding it vertical the other way and the vignette appeared on the left side.

I tried moving my lights around, changing my shutter and apperture, and I removed the hood, but all yielded the same result.

any ideas?

Are you talking about a dark bar across the bottom of the frame? If so, check your shutter speed. Make sure it's at or below max sync speed (1/250).

I think PacAce is right. Is it a dark bar across the bottom or just the corners? Better yet, do you have an example?

thanks PacAce, I think you may have hit the nail on the head. I was faster than that.
Can you tell me if I can shoot with a faster sync speed if I use my 550 flash to trigger the strobes. I know that my max sync speed is higher than 250 if I use the 550 flash by itself?

Yep - the shutter speed is set too fast. Use 1/250 or slower shutter speeds with the 30D and studio lights. You might not even be able to use 1/250 if you are using cheap radio slave equipment.

With a wired connection, 1/250 should work fine unless the optical slaves of the non-wired units are a bit on the slow side. That usually is not a problem, though.

ghostleemoe wrote in post #2977494
thanks PacAce, I think you may have hit the nail on the head. I was faster than that.
Can you tell me if I can shoot with a faster sync speed if I use my 550 flash to trigger the strobes. I know that my max sync speed is higher than 250 if I use the 550 flash by itself?

Your max sync speed is purely a function of the design of the focal plane shutter.

You cannot use the 550 at shutter speeds faster than the max sync speed without using the "high speed sync" mode. In that mode, the 550EX emits a series of weak pulses of light and NOT a single pulse. It is, essentially, painting the subject with light. If the 550EX is used in a normal mode, you cannot exceed the max sync speed without the black bar appearing on the one side of your images.

If you don't understand the concept of a focal plane shutter, I and others would be very willing to describe it for you.

ghostleemoe wrote in post #2977494
thanks PacAce, I think you may have hit the nail on the head. I was faster than that.
Can you tell me if I can shoot with a faster sync speed if I use my 550 flash to trigger the strobes. I know that my max sync speed is higher than 250 if I use the 550 flash by itself?

No. Max sync speed is fixed at 1/250 on the 30D. You can use a faster shutter speed with the 550EX if you set the flash to HSS (high-speed sync) mode but this only works with the flash itself and when it's attached directly on the hotshoe, via an off-shoe cord 2 cable or if the flash is in an ETTL wireless remote configuration controlled by a master. Unfortunately, this does not apply to strobes.

thanks for the help folks. I really appreciate it. I will go back to work with it tonight and since if I can't get this studio lighting stuff figured out.